The invention is generally related to expansion card mounting provisions in a computer enclosure, and in particular to Peripheral Component Interconnection (PCI) circuit board shield attachments to a housing of a computer enclosure.
General purpose computers are widely used in homes and businesses to perform many functions. Adapting general purpose computers to perform these varied functions is supported by a flexible architecture. Users may select among a variety of user interface peripheral devices, communication devices, and mass storage devices to configure a general purpose computer for a specific application.
An enclosure for general purpose computers, also referred to as computer chassis or case, supports a flexible computer architecture with provisions for internally mounting various devices such as circuit boards and disk drives. An enclosure also includes provisions for connecting to peripheral devices outside of the enclosure. Examples of such connections include parallel and serial ports.
The Peripheral Component Interconnect (PCI) standard is an example of an expansion card approach to support both objectives of supporting internal components and communicating with external devices. Expansion card slots within an enclosure provide space for additional circuit boards as well as electrical interconnections to other components within the enclosure, such as a parallel data bus to a motherboard. Each expansion card slot may have access to the exterior of the enclosure via an expansion slot opening in the enclosure for interconnections to peripheral devices. A PCI shield, or tail stock, registers over the expansion slot opening, making substantial electrical contact to the enclosure to provide Electromagnetic Compatibility (EMC), reducing radio frequency (RF) emissions from or into the enclosure via the expansion slot opening. The PCI shield also prevents cooling air flow from being inadvertently diverted and causing overheating within portions of the enclosure. In addition, the enclosure includes mountings for each PCI shield to physically secure the PCI shield in place, and any circuit board attached to the shield.
Mounting provisions for PCI shields are conventionally made with a large rectangular hole in the enclosure across which a PCI bracket is welded. A PCI bracket is typically capable of retaining multiple PCI shields. The PCI bracket conforms to the shape of PCI shields with physical retention provided by a combination of guides into which tongues defined at the ends of each of the multiple PCI shields may be slid to orient the PCI shields in a generally parallel relationship. Fasteners such as screws, flip latch mechanisms or clips are typically used to secure lateral tabs at the opposite ends of the PCI shields and thereby secure the shields within the PCI bracket. A PCI shield with no card attached (blanking cover) is used to close openings when no expansion card is needed.
Conventional PCI mounting provisions do secure the PCI shield, provide EMC features, and close the expansion slot opening to the expansion card slot. However, the requirement for a PCI bracket adds another component to the enclosure, as well as another manufacturing step to weld the PCI bracket to the enclosure. Similarly, the fastener for each expansion card slot increases the time required to assemble a general purpose computer or to perform upgrades and maintenance. Therefore, a significant need exists for an improved enclosure for a general purpose computer for mounting PCI expansion cards.
The invention addresses these and other problems associated with the prior art by providing an enclosure and method of making the same in which a housing and a cover are used to cooperatively retain an expansion card shield within the enclosure. In particular, an enclosure includes a housing with a receptor and a tab opening. The tab of the shield is allowed to extend through the tab opening when the shield is placed within the enclosure in a disengaged position. The tab opening is sized to allow the shield to be moved longitudinally to an engaged position wherein a tongue of the shield engages the receptor. The cover then retains the shield in the engaged position by restricting movement of the tab of the shield when the cover is secured to the enclosure.
In another aspect consistent with the invention, a method of making an enclosure for receiving a shield includes defining an expansion card shield mounting sized for the tongue of the shield. A tab opening in the panel is formed at a first end of the expansion card shield mounting, with the tab opening laterally sized to receive the tab of the shield with the tongue of the shield proximate to and aligned with the expansion card shield mounting. The tab opening is longitudinally sized to allow displacement of the tab along the longitudinal axis of the expansion card shield mounting between a disengaged position and an engaged position. A receptor is formed at a second end of the expansion card shield mounting longitudinally displaced from the tab opening sufficient to clear the tongue of the shield when the tab is inserted through the tab opening at the disengaged position and to engage the tongue of the shield when the tab is translated to the engaged position.
These and other advantages and features, which characterize the invention, are set forth in the claims annexed hereto and forming a further part hereof. However, for a better understanding of the invention, and of the advantages and objectives attained through its use, reference should be made to the Drawings, and to the accompanying descriptive matter, in which there are described exemplary embodiments of the invention.